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[VIC] 1990 CBR250RR Won't exceed 120km/ph

Discussion in 'Technical and Troubleshooting Torque' started by destroyer5787, May 7, 2008.

  1. The Scenario,

    Trying to pusht the limits of my bike, bike is warm, Open stretch of road on fwy, rev first gear out to 18 grand, speedo reads 70, shift, rev second gear to 18 grand, speedo reads approx 100, shift, rev bike out to 16 grand in third gear, speedo reads 120km/ph and it wont change, revs slowly creep up, so too does the speed but this takes too long, it seems like ages for it to shift past 120km/ph, bike is shaking i am going so fast, speedo still reads 120km/ph like its stuck. Try shifting to fourth gear, revs drop about 2 grand to 14000 bike creeps back up to 120, same thing....

    I do not understand what is wrong with my bike. Is this an issue with a rev restricter..?? Speedo works fine in normal operation, gauging my speed with other cars on the road, when i do 80 in an 80 zone, i am keeping up with traffic. when i get to 120km/ph i can feel the speed and my bike starts to shake a little.

    Or am i being chicken?? and not sticking it out long enough to let the revs and speed "slowly creep up", the issue is that comapred to the frist 2 gears, the third gear takes a really, really long time, i have only been able to get it maybe 2mm past the 120 line and then i was holding it open throttle on third for a long long time.

    If anyone knows what is happening here please help....

  2. It's 18 years old and has undoubtedly had numerous previous owners treating it exactly the same way you are.
  3. +1
  4. +1!


    PM me and ill have a look at it if you want...
  5. Simply put, your engine is down on power and this becomes evident as the gearing becomes taller.
    There are many reasons it could be down but I'd start with a carb balance and compression test.
  6. Max power is made around 14,500 rpm on my FZR250 so try sticking to a gear around that rpm mark.

    Sounds like the engine is down on power or you are a big hefalump as my FZR250R starts to run out of puff at around 160.
  7. [devil's advocate] But the speed limit in vic is only 100km/h... so what's the problem? :twisted: :twisted: :twisted: [/da]
  8. It's only a year younger than you; how fast were YOU when you were one??? :LOL:.

  9. HAHAH, yes thats true!!!

    but in the interest of maintaining my license and 2 demerit points i have left, i suppose it is good for me being somewhat restricted....

    However its still not nice knowing that your bike is down on power, and not running in optimal condition. :( and i havent even ridden with my mates yet, which could prove to be embarrassing :twisted: :shock: :( :oops:
  10. My CBR250RR got to 160km/h (only on the track ofcourse :p ) but thats where it stayed....

    I noticed that your 1st gear only goes to 70... my revlimiter kicked in right on 80km/h... maybe your gearing is different for quicker pulls, but less top end...

    But certainly start with a tune-up firstly, you could also try putting it onto a race stand, securing it, and then kick it into gear and rev it out, see what top speed you can get to without the friction of the road and will tell you if your speedo is broken...
    Dont do this for long tho, unless you have a fan pointed at the radiator, like in a dyno situation...
  12. Dont worry, you wont need a fan. Reving out with no load and you will be picking up pieces of engine long before the lack of cooling becomes an issue.
  13. There are so many things wrong with this advice I want it on video if you do it :LOL:
  14. Great advice booga i often do this myself in the loungeroom in front of the tv watchin the grand prix like im there LOL!!!
  15. Haven't exactly rev'd it "out"... but as long as your bike is working fine there should be no issue, it still the same as having load on it... Your oil and radiator still work, they're not road driven :p

    But i DID have mine on the stand and had it over 100km/h and no issue... so whats yours? :p
  16. 100kph missile in the shed is destined for youtube. :LOL:
  17. Simply if it goes to sh!t it will bounce around the garage like a pinball. Thats what I want on tape :LOL:
  18. :rofl: Yeah, could become interesting... but yeah, thats why i tried to be sensible and add "secure" to my original suggestion, spose i should have provided some entertainmen by not saying anything ;)
  19. Well it turns out my speedo is broken, it doesnt work properly past 120km/h, i past my mate who was doing 160, and in his opinion i was doing close to 180, i thought cbrs had a max speed of 150 but hey, if i past my mate and was going that fast....whooohooo it felt goood ;)
  20. You can't tell the difference between 120kph and 180kph without a speedo? :shock:
    Hope you've got a bus pass or decent pushy, you may be needing it soon.